Replies

1. Expert Member
   BILL WICHERS | Jan 04, 2022 11:50am | #1

   I haven't used that specific product, but I do have a lot of experience working with HDPE in generic forms. You can't glue anything to it (but you can weld it -- thermally, not with solvent), and I doubt very much any kind of paint is going to stick to it, so you're stuck with whatever color it was made originally. It cuts pretty easily with regular saws, but has a tendency to leave little "stringies" on the edges that you can trim off with a knife. If you are using a smooth surface version without a texture, note that it will scratch and mar VERY easily since it's a relatively soft material. I think that scratching and marring issue is probably the biggest downside to using this material for trim work.

   On the plus side, it's a pretty impervious material that won't react with anything, so it will last forever. You have to be sure it's a UV resistant version though. The "nothing will stick well" problem will also affect caulking -- I would expect it to be very difficult to get a long-term reliable seal.

   I think you'd be better off with the PVC trim products over HDPE. The reasons for this is that PVC is paintable if you're careful, can be solvent welded, and you can caulk to it to seal things. You also have all the different profiles available, so you have more flexibility.

   Bill

2. GBA Editor
   Kiley Jacques | Jan 04, 2022 12:49pm | #2

   This is great information, Bill. Thanks for taking the time to share it. I will pass it on to the FHB podcast listener who was inquiring about the product.

3. 
   charlie_sullivan | Jan 04, 2022 01:04pm | #3

   I'm not sure if it was the same product but I bought something similar to repair a sailboat once (after the rudder fell off in the middle of a bay--but that's a story for another time). It worked very well for that purpose and I'd used some of the the leftovers for miscellaneous purposes, including a mounting block for attaching aluminum stair stringers to a deck, where it has held up well in the weather.

   The material I got was sufficiently textured that Bill's concern about scratching wasn't much of an issue, but I agree that that would be an issue if it wasn't textured, and I agree that paint is unlikely to stick, so you need to get the color you want.

   In addition, HDPE has more than twice the thermal expansion that PVC has. Given that that's already an issue in PVC trim, and the mounting systems accommodate that, it could be a bigger problem with HDPE.

   So while it's a good material, the scope of where it would work well is pretty narrow.

4. Expert Member
   MALCOLM TAYLOR | Jan 04, 2022 01:40pm | #4

   Kiley,

   I use HDPE in two applications.

   - As guides and jigs on my saws.
   - As capillary breaks on the bottom of wood posts.

5. GBA Editor
   Kiley Jacques | Jan 04, 2022 04:33pm | #5

   Thanks, guys. I shared this with listeners, and learned that it is also used in the making of outdoor furniture, drawer slides, skate boarding ramps, cutting boards, and all sorts of things. But trim--that doesn't seem like a good plan. I pointed him in the direction of Boral TruExterior.

1. Expert Member
   BILL WICHERS | Jan 04, 2022 05:26pm | #6

   UHMW (Ultra High Molecular Weight) polyethylene is great for wear surfaces like drawer slides. You can get UHMW tape that has an adhesive backer, I've used it to retrofit "glides" onto drawers in older homes. UHMW is much better than the old wood riding on a plastic roller (that would tend to break).

   Bill